This invention relates to superabrasive tools such as rim wheels and wheel segments which comprise a superabrasive grain such as diamond or cubic boron nitride, (CBN).
Tools containing superabrasives are widely used for cutting extremely tough materials such as concrete for example. It is found however that the cost of such wheels is very high because the superabrasive component itself is very expensive. There is therefore considerable interest in the production of tools that are very effective and at the same time less expensive than tools in which the superabrasive component provides 100% of the abrasive content.
One such approach is illustrated in U.S. Pat. Nos. 5,152,810 and 4,944,773 in which part of the superabrasive component is replaced by a sol-gel alumina abrasive with surprisingly advantageous results and a significantly lowered cost.
The present invention provides a further advance in such technologies by providing the sol-gel alumina in a form conferring advantages in a highly efficient manner and adding new possibilities not described in the prior art.